摘要
在库水位升降及降雨作用下,三峡库区不少土质滑坡出现周期性阶跃变形,此类滑坡变形机理复杂,预警预报难。以典型涉水土质滑坡卧沙溪滑坡为例,通过10多年野外宏观巡查资料、13年的人工监测和4年的全自动监测数据,揭示卧沙溪滑坡次级滑体的变形机理,建立降雨及库水位相关阈值。结果表明:(1)次级滑体变形的主控因素由库水位下降和库水浸泡转变为持续性降雨。(2)持续性降雨导致坡体变形,监测点位移速率“峰值滞后”效应为1~2 d,位移速率衰减时间为5~9 d。(3)降雨及库水位阈值:30 d累积降雨量阈值150 mm,且变形前1 d降雨量40 mm;变形启动3 d内,累积降雨量超过50 mm会加速坡体变形,且变形时间延长。库水位下降至146 m前30 d累积降雨量115 mm,库水位下降速率阈值为0.8 m/d。研究成果可为类似滑坡的监测预警提供参考。
Owing to the rise and fall of reservoir water levels and rainfall events,several soil landslides show periodic step deformation.The deformation mechanism of such landslides is complex,and forewarning and forecasting of landslides are difficult.With the Woshaxi landslide as the research object,the deformation mechanism of secondary sliding mass was revealed,and the thresholds of rainfall and reservoir water level were revealed through more than 10 years of field inspection,13 years of artificial monitoring data,and 4 years of automatic monitoring data.It was found that(1)the main factors controlling the deformation of secondary sliding mass change from reservoir water level drop and reservoir water immersion to continuous rainfall.(2)Continuous rainfall gives rise to slope deformation;the time of the“peak-value delay”effect of the deformation rate caused by rainfall is about 1-2 days,and the decay time of the displacement rate lasts about 5-9 days.(3)The cumulative rainfall threshold for 30 days is 150 mm,and 1-day rainfall before deformation is 40 mm;moreover,within 3 days after the deformation initiation,the accumulated rainfall exceeding 50 mm will accelerate the slope deformation and prolong the deformation time.The cumulative rainfall of 30 days before the reservoir water level decreases to 146 m is 115 mm,and the decline rate threshold of the reservoir water level is 0.8 m/d.This work offers a reference for monitoring and early warning of similar landslides.
作者
周露露
邓茂林
易庆林
王国法
梁之康
万航
ZHOU Lulu;DENG Maolin;YI Qinglin;WANG Guofa;LIANG Zhikang;WAN Hang(National Field Observation and Research Station of Landslides in Three Gorges Reservoir Area of Yangtze River,Yichang 443002,Hubei,China;School of Civil Engineering and Architecture,China Three Gorges University,Yichang 443002,Hubei,China;Chongqing 107 Municipal Construction Engineering Co.,Ltd.,Chongqing 401120,China)
出处
《地震工程学报》
CSCD
北大核心
2023年第5期1125-1132,共8页
China Earthquake Engineering Journal
基金
国家自然科学基金项目(42172303)。
关键词
阈值
变形机理
库水位
降雨
threshold value
deformation mechanism
reservoir water level
rainfall
